stat_sinks: add OpenTelemetry stats sink

CODEOWNERS

@@ -125,6 +125,7 @@ extensions/filters/common/original_src @snowp @klarose
 /*/extensions/stat_sinks/graphite_statsd @vaccarium @mattklein123
 /*/extensions/stat_sinks/hystrix @trabetti @jmarantz
 /*/extensions/stat_sinks/metrics_service @ramaraochavali @jmarantz
+/*/extensions/stat_sinks/open_telemetry @ohadvano @mattklein123
 # webassembly stat-sink extensions
 /*/extensions/stat_sinks/wasm @mpwarres @mathetake @lizan
 /*/extensions/resource_monitors/injected_resource @eziskind @htuch

api/BUILD

@@ -286,6 +286,7 @@ proto_library(
         "//envoy/extensions/retry/host/previous_hosts/v3:pkg",
         "//envoy/extensions/retry/priority/previous_priorities/v3:pkg",
         "//envoy/extensions/stat_sinks/graphite_statsd/v3:pkg",
+        "//envoy/extensions/stat_sinks/open_telemetry/v3:pkg",
         "//envoy/extensions/stat_sinks/wasm/v3:pkg",
         "//envoy/extensions/transport_sockets/alts/v3:pkg",
         "//envoy/extensions/transport_sockets/http_11_proxy/v3:pkg",

api/bazel/external_proto_deps.bzl

@@ -34,6 +34,7 @@ EXTERNAL_PROTO_GO_BAZEL_DEP_MAP = {
     "@opencensus_proto//opencensus/proto/trace/v1:trace_config_proto": "@opencensus_proto//opencensus/proto/trace/v1:trace_and_config_proto_go",
     "@opentelemetry_proto//:trace": "@opentelemetry_proto//:trace_go_proto",
     "@opentelemetry_proto//:logs": "@opentelemetry_proto//:logs_go_proto",
+    "@opentelemetry_proto//:metrics": "@opentelemetry_proto//:metrics_go_proto",
     "@opentelemetry_proto//:common": "@opentelemetry_proto//:common_go_proto",
 }
 
@@ -45,6 +46,7 @@ EXTERNAL_PROTO_CC_BAZEL_DEP_MAP = {
     "@opencensus_proto//opencensus/proto/trace/v1:trace_config_proto": "@opencensus_proto//opencensus/proto/trace/v1:trace_config_proto_cc",
     "@opentelemetry_proto//:trace": "@opentelemetry_proto//:trace_cc_proto",
     "@opentelemetry_proto//:logs": "@opentelemetry_proto//:logs_cc_proto",
+    "@opentelemetry_proto//:metrics": "@opentelemetry_proto//:metrics_cc_proto",
     "@opentelemetry_proto//:common": "@opentelemetry_proto//:common_cc_proto",
 }
 
@@ -56,5 +58,6 @@ EXTERNAL_PROTO_PY_BAZEL_DEP_MAP = {
     "@opencensus_proto//opencensus/proto/trace/v1:trace_config_proto": "@opencensus_proto//opencensus/proto/trace/v1:trace_config_proto_py",
     "@opentelemetry_proto//:trace": "@opentelemetry_proto//:trace_py_proto",
     "@opentelemetry_proto//:logs": "@opentelemetry_proto//:logs_py_proto",
+    "@opentelemetry_proto//:metrics": "@opentelemetry_proto//:metrics_py_proto",
     "@opentelemetry_proto//:common": "@opentelemetry_proto//:common_py_proto",
 }

api/bazel/repositories.bzl

@@ -163,6 +163,26 @@ go_proto_library(
     visibility = ["//visibility:public"],
 )
 
+api_cc_py_proto_library(
+    name = "metrics",
+    srcs = [
+        "opentelemetry/proto/collector/metrics/v1/metrics_service.proto",
+        "opentelemetry/proto/metrics/v1/metrics.proto",
+    ],
+    deps = [
+        "//:common",
+        "//:resource",
+    ],
+    visibility = ["//visibility:public"],
+)
+
+go_proto_library(
+    name = "metrics_go_proto",
+    importpath = "go.opentelemetry.io/proto/otlp/metrics/v1",
+    proto = ":metrics",
+    visibility = ["//visibility:public"],
+)
+
 api_cc_py_proto_library(
     name = "trace",
     srcs = [

api/envoy/extensions/stat_sinks/open_telemetry/v3/BUILD

@@ -0,0 +1,12 @@
+# DO NOT EDIT. This file is generated by tools/proto_format/proto_sync.py.
+
+load("@envoy_api//bazel:api_build_system.bzl", "api_proto_package")
+
+licenses(["notice"])  # Apache 2
+
+api_proto_package(
+    deps = [
+        "//envoy/config/core/v3:pkg",
+        "@com_github_cncf_udpa//udpa/annotations:pkg",
+    ],
+)

api/envoy/extensions/stat_sinks/open_telemetry/v3/open_telemetry.proto

@@ -0,0 +1,47 @@
+syntax = "proto3";
+
+package envoy.extensions.stat_sinks.open_telemetry.v3;
+
+import "envoy/config/core/v3/grpc_service.proto";
+
+import "google/protobuf/wrappers.proto";
+
+import "udpa/annotations/status.proto";
+import "validate/validate.proto";
+
+option java_package = "io.envoyproxy.envoy.extensions.stat_sinks.open_telemetry.v3";
+option java_outer_classname = "OpenTelemetryProto";
+option java_multiple_files = true;
+option go_package = "github.com/envoyproxy/go-control-plane/envoy/extensions/stat_sinks/open_telemetry/v3;open_telemetryv3";
+option (udpa.annotations.file_status).package_version_status = ACTIVE;
+
+// [#protodoc-title: Open Telemetry Stats Sink]
+// Stats configuration proto schema for ``envoy.stat_sinks.open_telemetry`` sink.
+// [#extension: envoy.stat_sinks.open_telemetry]
+
+// [#next-free-field: 6]
+message SinkConfig {
+  oneof protocol_specifier {
+    option (validate.required) = true;
+
+    // The upstream gRPC cluster that implements the OTLP/gRPC collector.
+    config.core.v3.GrpcService grpc_service = 1 [(validate.rules).message = {required: true}];
+  }
+
+  // If set to true, counters will be emitted as deltas, and the OTLP message will have
+  // ``AGGREGATION_TEMPORALITY_DELTA`` set as AggregationTemporality.
+  bool report_counters_as_deltas = 2;
+
+  // If set to true, histograms will be emitted as deltas, and the OTLP message will have
+  // ``AGGREGATION_TEMPORALITY_DELTA`` set as AggregationTemporality.
+  bool report_histograms_as_deltas = 3;
+
+  // If set to true, metrics will have their tags emitted as OTLP attributes, which may
+  // contain values used by the tag extractor or additional tags added during stats creation.
+  // Otherwise, no attributes will be associated with the export message. Default value is true.
+  google.protobuf.BoolValue emit_tags_as_attributes = 4;
+
+  // If set to true, metric names will be represented as the tag extracted name instead
+  // of the full metric name. Default value is true.
+  google.protobuf.BoolValue use_tag_extracted_name = 5;
+}

api/versioning/BUILD

@@ -225,6 +225,7 @@ proto_library(
         "//envoy/extensions/retry/host/previous_hosts/v3:pkg",
         "//envoy/extensions/retry/priority/previous_priorities/v3:pkg",
         "//envoy/extensions/stat_sinks/graphite_statsd/v3:pkg",
+        "//envoy/extensions/stat_sinks/open_telemetry/v3:pkg",
         "//envoy/extensions/stat_sinks/wasm/v3:pkg",
         "//envoy/extensions/transport_sockets/alts/v3:pkg",
         "//envoy/extensions/transport_sockets/http_11_proxy/v3:pkg",

changelogs/current.yaml

@@ -35,9 +35,14 @@ new_features:
     added Runtime feature ``envoy.reloadable_features.max_request_headers_size_kb`` to override the default value of
     :ref:`max request headers size
     <envoy_v3_api_field_extensions.filters.network.http_connection_manager.v3.HttpConnectionManager.max_request_headers_kb>`.
+- area: stat_sinks
+  change: |
+    Added ``envoy.stat_sinks.open_telemetry`` stats_sink, that supports flushing metrics by the OTLP protocol,
+    for supported Open Telemetry collectors.
 - area: redis_proxy
   change: |
     added new configuration field :ref:`key_formatter
     <envoy_v3_api_field_extensions.filters.network.redis_proxy.v3.RedisProxy.PrefixRoutes.Route.key_formatter>` to format redis key.
     The field supports using %KEY% as a formatter command for substituting the redis key as part of the substitution formatter expression.
+
 deprecated:

docs/root/api-v3/config/stat_sinks/stat_sinks.rst

@@ -6,4 +6,5 @@ Stat sinks
   :maxdepth: 2
 
   ../../extensions/stat_sinks/graphite_statsd/v3/*
+  ../../extensions/stat_sinks/open_telemetry/v3/*
   ../../extensions/stat_sinks/wasm/v3/*

docs/root/configuration/observability/stat_sinks/open_telemetry_stat_sink.rst

@@ -0,0 +1,12 @@
+.. _config_stat_sinks_open_telemetry:
+
+OpenTelemetry Stat Sink
+=========================
+
+The :ref:`OpenTelemetryStatsSink <envoy_v3_api_msg_extensions.stat_sinks.open_telemetry.v3.SinkConfig>` configuration specifies a
+stat sink that emits stats according to `OpenTelemetry Protocol Specification <https://opentelemetry.io/docs/reference/specification/protocol/otlp/>`_.
+The export requests of this sink are sent to the collector service according to the Protobuf defined in
+`MetricService/Export <https://github.com/open-telemetry/opentelemetry-proto/blob/main/opentelemetry/proto/collector/metrics/v1/metrics_service.proto>`_.
+The metric resources exported are defined in `metrics.proto <https://github.com/open-telemetry/opentelemetry-proto/blob/main/opentelemetry/proto/metrics/v1/metrics.proto>`_.
+Any export request that this sink sends, will contain a single ``ResourceMetrics`` message, a single ``ScopeMetrics`` and repeated ``MetricRecord``,
+according to the number of metrics collected during the proccess run.

docs/root/configuration/observability/stat_sinks/stat_sinks.rst

@@ -5,4 +5,5 @@ Stat sinks
   :maxdepth: 2
 
   graphite_statsd_stat_sink
+  open_telemetry_stat_sink
   wasm_stat_sink

source/extensions/extensions_build_config.bzl

@@ -214,6 +214,7 @@ EXTENSIONS = {
     "envoy.stat_sinks.graphite_statsd":                 "//source/extensions/stat_sinks/graphite_statsd:config",
     "envoy.stat_sinks.hystrix":                         "//source/extensions/stat_sinks/hystrix:config",
     "envoy.stat_sinks.metrics_service":                 "//source/extensions/stat_sinks/metrics_service:config",
+    "envoy.stat_sinks.open_telemetry":                  "//source/extensions/stat_sinks/open_telemetry:config",
     "envoy.stat_sinks.statsd":                          "//source/extensions/stat_sinks/statsd:config",
     "envoy.stat_sinks.wasm":                            "//source/extensions/stat_sinks/wasm:config",
 

source/extensions/extensions_metadata.yaml

@@ -1026,6 +1026,13 @@ envoy.stat_sinks.metrics_service:
   status: stable
   type_urls:
   - envoy.config.metrics.v3.MetricsServiceConfig
+envoy.stat_sinks.open_telemetry:
+  categories:
+  - envoy.stats_sinks
+  security_posture: data_plane_agnostic
+  status: alpha
+  type_urls:
+  - envoy.extensions.stat_sinks.open_telemetry.v3.SinkConfig
 envoy.stat_sinks.statsd:
   categories:
   - envoy.stats_sinks

source/extensions/stat_sinks/open_telemetry/BUILD

@@ -0,0 +1,45 @@
+load(
+    "//bazel:envoy_build_system.bzl",
+    "envoy_cc_extension",
+    "envoy_cc_library",
+    "envoy_extension_package",
+)
+
+licenses(["notice"])  # Apache 2
+
+envoy_extension_package()
+
+envoy_cc_library(
+    name = "open_telemetry_lib",
+    srcs = ["open_telemetry_impl.cc"],
+    hdrs = ["open_telemetry_impl.h"],
+    deps = [
+        "//envoy/grpc:async_client_interface",
+        "//envoy/singleton:instance_interface",
+        "//source/common/grpc:async_client_lib",
+        "@envoy_api//envoy/extensions/stat_sinks/open_telemetry/v3:pkg_cc_proto",
+        "@opentelemetry_proto//:metrics_cc_proto",
+    ],
+)
+
+envoy_cc_library(
+    name = "open_telemetry_proto_descriptors_lib",
+    srcs = ["open_telemetry_proto_descriptors.cc"],
+    hdrs = ["open_telemetry_proto_descriptors.h"],
+    deps = [
+        "//source/common/common:assert_lib",
+        "//source/common/protobuf",
+    ],
+)
+
+envoy_cc_extension(
+    name = "config",
+    srcs = ["config.cc"],
+    hdrs = ["config.h"],
+    deps = [
+        ":open_telemetry_lib",
+        ":open_telemetry_proto_descriptors_lib",
+        "//envoy/registry",
+        "//source/server:configuration_lib",
+    ],
+)

source/extensions/stat_sinks/open_telemetry/config.cc

@@ -0,0 +1,60 @@
+#include "source/extensions/stat_sinks/open_telemetry/config.h"
+
+#include "envoy/registry/registry.h"
+
+#include "source/extensions/stat_sinks/open_telemetry/open_telemetry_impl.h"
+#include "source/extensions/stat_sinks/open_telemetry/open_telemetry_proto_descriptors.h"
+
+namespace Envoy {
+namespace Extensions {
+namespace StatSinks {
+namespace OpenTelemetry {
+
+Stats::SinkPtr
+OpenTelemetrySinkFactory::createStatsSink(const Protobuf::Message& config,
+                                          Server::Configuration::ServerFactoryContext& server) {
+  validateProtoDescriptors();
+
+  const auto& sink_config = MessageUtil::downcastAndValidate<const SinkConfig&>(
+      config, server.messageValidationContext().staticValidationVisitor());
+
+  auto otlp_options = std::make_shared<OtlpOptions>(sink_config);
+  std::shared_ptr<OtlpMetricsFlusher> otlp_metrics_flusher =
+      std::make_shared<OtlpMetricsFlusherImpl>(otlp_options);
+
+  switch (sink_config.protocol_specifier_case()) {
+  case SinkConfig::ProtocolSpecifierCase::kGrpcService: {
+    const auto& grpc_service = sink_config.grpc_service();
+
+    std::shared_ptr<OpenTelemetryGrpcMetricsExporter> grpc_metrics_exporter =
+        std::make_shared<OpenTelemetryGrpcMetricsExporterImpl>(
+            otlp_options,
+            server.clusterManager().grpcAsyncClientManager().getOrCreateRawAsyncClient(
+                grpc_service, server.scope(), false));
+
+    return std::make_unique<OpenTelemetryGrpcSink>(otlp_metrics_flusher, grpc_metrics_exporter);
+  }
+
+  default:
+    break;
+  }
+
+  throw EnvoyException("unexpected Open Telemetry protocol case num");
+}
+
+ProtobufTypes::MessagePtr OpenTelemetrySinkFactory::createEmptyConfigProto() {
+  return std::make_unique<SinkConfig>();
+}
+
+std::string OpenTelemetrySinkFactory::name() const { return OpenTelemetryName; }
+
+/**
+ * Static registration for the this sink factory. @see RegisterFactory.
+ */
+LEGACY_REGISTER_FACTORY(OpenTelemetrySinkFactory, Server::Configuration::StatsSinkFactory,
+                        "envoy.open_telemetry_stat_sink");
+
+} // namespace OpenTelemetry
+} // namespace StatSinks
+} // namespace Extensions
+} // namespace Envoy

source/extensions/stat_sinks/open_telemetry/config.h

@@ -0,0 +1,34 @@
+#pragma once
+
+#include "envoy/registry/registry.h"
+#include "envoy/server/instance.h"
+
+#include "source/server/configuration_impl.h"
+
+namespace Envoy {
+namespace Extensions {
+namespace StatSinks {
+namespace OpenTelemetry {
+
+constexpr char OpenTelemetryName[] = "envoy.stat_sinks.open_telemetry";
+
+/**
+ * Config registration for the OpenTelemetry stats sink. @see StatsSinkFactory.
+ */
+class OpenTelemetrySinkFactory : Logger::Loggable<Logger::Id::config>,
+                                 public Server::Configuration::StatsSinkFactory {
+public:
+  Stats::SinkPtr createStatsSink(const Protobuf::Message& config,
+                                 Server::Configuration::ServerFactoryContext& server) override;
+
+  ProtobufTypes::MessagePtr createEmptyConfigProto() override;
+
+  std::string name() const override;
+};
+
+DECLARE_FACTORY(OpenTelemetrySinkFactory);
+
+} // namespace OpenTelemetry
+} // namespace StatSinks
+} // namespace Extensions
+} // namespace Envoy